Modding Greengage for better bass/bass guitar?
- Thread starter jrhevron
- Start date
C1 appears to be letting all the bass through as is. Upping it won’t hurt be I doubt it would help. C6 sets the frequency of the tone knob, changing it may or may not be what you want.
the place where bass loos is occurring is C4 & R6. It’s cutting bass around 340Hz, which is already more bass than the typical TS pedal (cuts bass below 723Hz). I’d experiment with either increasing C4, or adding a bass pot (something like the picture, experiment with values).
the place where bass loos is occurring is C4 & R6. It’s cutting bass around 340Hz, which is already more bass than the typical TS pedal (cuts bass below 723Hz). I’d experiment with either increasing C4, or adding a bass pot (something like the picture, experiment with values).
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Thank you for the response!
What would you change C4 and R6 to?
Over on PCB Effects layouts, the suggestion is to change C4 to "anything from 1 to 10uF"
What would you change C4 and R6 to?
Over on PCB Effects layouts, the suggestion is to change C4 to "anything from 1 to 10uF"
Experiment and see. Or put an on-off-on switch to select different values in parallel with C4. Above 1u the differences will be slighter. I’d focus on experimenting between 100n and 2u2.
C4 and R6 together affect the frequency cutoff. But, R6 also affects the amount of gain. So, I’d probably keep R6 as is to avoid altering the gain range, and just mess with C4.
C4 and R6 together affect the frequency cutoff. But, R6 also affects the amount of gain. So, I’d probably keep R6 as is to avoid altering the gain range, and just mess with C4.
ErickPulido
Active member
as Phi1 said experiment with the cap, one good example is the dwarven hammer look at the schematic for reference and the stockade overdrive is another good one
Looks like the Dwarven Hammer uses a 220n in a similar spot on the schematic. I'm not great at reading schematics, but that seems close to where I'd want to be looking. 330n on the stockade.
ErickPulido
Active member
it uses 8 different caps : 470n, 330n, 220n, 100n, 82n, 68n, 47n and 33n
I need to go higher than 100n, so seems like 470-220 is a good range to try.
I think 1 resistor, and 2 caps, right? He seems to be a bit cagey about it in the post intentionally,at be he didn’t want to share for some reason. C4 is the main low end loss culprit, maybe I’m wrong and upping C1 is a bigger difference than I thought. Or he changed one of the many caps that control high frequency cut off. Not sure why he needed to mess with an R, there’s plenty of things you could tweak slightly. My recommendation would be to focus on C4 area.
To be fair to John, sometimes I think he does the mod that sounds good and then doesn't really write down what he does and that's why he can't share it. For his pork loin mod, he documented that one pretty well.
Very cool he replied with that detail. Background about my comments regarding C1 in case you’re interested.
33n followed by 10M to ground. This forms a high pass (bass cut) filter with the values of C1 and the 10M resistor (in parallel with the input impedance of the op amp, which I don’t know, but I think is pretty high). Even if the input impedance of the op amp were as low as 1M (I doubt it is), 33n and 1M puts the cutoff frequency at 4.8Hz. Again, I could be missing something, so if you find there is a difference, please let me know.
33n followed by 10M to ground. This forms a high pass (bass cut) filter with the values of C1 and the 10M resistor (in parallel with the input impedance of the op amp, which I don’t know, but I think is pretty high). Even if the input impedance of the op amp were as low as 1M (I doubt it is), 33n and 1M puts the cutoff frequency at 4.8Hz. Again, I could be missing something, so if you find there is a difference, please let me know.
Gonna have to try this tonight... I have an actual Plumes pedal that I'm going to mod-- and build a greengage if I can't. The eqd photos all had through hole components, but my pedal is SMD. I can see that you can carefully make regular caps work here... will just have to figure that out tonight. I've never done that myself.
Option 1: the plumes seems to be extremely popular, you could probably sell it as is
Option 2: mod existing. R4 on EQD seems to be R6 on pedalpcb. Verify that with multimeter continuity check (beep setting). Then using continuity check, fugues out which cap is pedalpcb C4. I don’t recommend removing this smd cap. Rather, add another capacitor in parallel. (With caps in parallel, add values for total capacitance.)
ive heard caps are the most damageable smd part for hand soldering, so I’d recommend adding some wires to other solder joints that connect to the cap (like from the op amp and R4).
Option 2: mod existing. R4 on EQD seems to be R6 on pedalpcb. Verify that with multimeter continuity check (beep setting). Then using continuity check, fugues out which cap is pedalpcb C4. I don’t recommend removing this smd cap. Rather, add another capacitor in parallel. (With caps in parallel, add values for total capacitance.)
ive heard caps are the most damageable smd part for hand soldering, so I’d recommend adding some wires to other solder joints that connect to the cap (like from the op amp and R4).
I think that maybe the ideal test, if the cap values add up, is to hook up my looper to the open pedal and send a bass loop through. Then just try a few different caps and press the leads up against the sides of the SMD cap to see how that changes things.
Did the cap mod work for you? I’m waiting for greengage to come back in stock to try this.
Did the cap mod work for you? I’m waiting for greengage to come back in stock to try this.
I'm not sure why, but I couldn't make this work... it was kind of a half ass strategy anyway. That said, I've come to appreciate my plumes more lately. It's a fine standalone OD that does lose a little low end. However, I'm finding that it's really good as a sweetener before a muff. Really gives the muff more of a mid/3D kind of feel. Also, when I run my Diamond bass comp at the end of the line, it adds all of the bass back into the signal. Let me know how your build goes.
